The present invention relates to the manufacture of semiconductor devices and more particularly to the formation of a cap to protect an underlying metal layer.
Manufacture of semiconductor devices typically involves a series of processes in which various layers are deposited and patterned on a substrate to form a device of the desired type. Many semiconductor devices have a number of metal layers formed thereon and interconnected using vias. Typically, the top metal layer may have pads that are used for interconnection and sort probing. In certain devices, a cap is formed above the top metal layer to provide a location to bond wires for electrical connections. Further, the cap may be used to protect the metal layer during sort probing.
However, problems exist with formation of the cap. As a result of misalignment of the cap, a portion of the metal layer is exposed, which is undesirable, as the metal layer is unstable in an ambient environment. Also, the force of a sort probe on the cap can cause probe marks, which can also expose portions of the metal layer and even cause cracking of the metal layer, which can propagate to the lower metal layers, either immediately or during the later bonding. Thus a need exists to protect and to avoid exposure of the underlying metal layer.